                        ;'(signal_error)
                        [0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0]
                        [(tag-instruction-erc [:exec])]
-                       (for [t (vals button-entrypoints)]
-                         (fn [] (symbol (str "tag_exec_" (str t)))))
+                       ;(for [t (vals button-entrypoints)]
+                       ;  (fn [] (symbol (str "tag_exec_" (str t)))))
                        [(tagged-instruction-erc)]
+                       ;; allow code_append tag macros (taking 2 arguments and returning 1 result)
+                       [(tagged-code-macro-erc 'code_append @global-tag-limit 2 1)]
                        ;(repeat 46 'code_noop)
                        '(boolean_and
                           boolean_dup

   :reproduction-simplifications 10
   :ultra-probability 1.0
   :ultra-alternation-rate 0.005
   :ultra-alignment-deviation 50
   :ultra-mutation-rate 0.005
   :deletion-mutation-probability 0
   :parentheses-addition-mutation-probability 0

        [clojush.random]
        [clojush.util]
        [clojush.instructions.tag]
        [clojure.math.numeric-tower]        
        [clojush.globals]
        [clojush.experimental.tagged-code-macros]
        ;[incanter.stats :as stats]
        ))

